| | 1 | Author
| D. Ietm Ar Kuek, Andreas Schuster | Requires cookie* | | | Title
| Oxidations of Alkylbenzenes with Dimethyldioxirane  | | | | Abstract
| The oxidation o f various alkylbenzenes (1 -1 7) with excess dim ethyldioxirane (D M D O) in hom ogeneous acetone solutions has been studied. In general, the benzylic methylene and methine C -H bonds were oxidized to give the corresponding phenones and tertiary benzylic alcohols, respectively, in relatively low yields. W hereas a tert-buiy\ substituent at the reaction centre leads to very low conversion due to steric hindrance, the presence o f additional phenyl groups appears to favour the oxidation in most, but not all cases. Di-and triphenylmethane (4 and 14) were found to be considerably less reactive than cw-decalin. By contrast, the intra molecular competetive oxidation o f isobutylbenzene (19) and l-m ethyl-4-phenylcyclohexanes (20) reveals that the benzylic C -H bonds are slightly more reactive than the tertiary ones at remote positions. | | | |
Reference
| Z. Naturforsch. 46b, 1223—1226 (1991); received April 4 1991 | | | |
Published
| 1991 | | | |
Keywords
| D ioxiranes, Dimethyldioxirane, Alkylbenzenes, Oxidation | | | |
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| default:Reihe_B/46/ZNB-1991-46b-1223.pdf | | | | Identifier
| ZNB-1991-46b-1223 | | | | Volume
| 46 | |
| 2 | Author
| WolfdieterA. Schenk, Bernhard Steinmetz3, Michael Hagel3, Waldemar Adamb, ChantuR. Saha-Möllerb | Requires cookie* | | | Title
| Oxyfunctionalization of Allyl Thioether Ruthenium Complexes with Dimethyldioxirane [1] | | | | Abstract
| Allyl thioether complexes [CpRu(P-P)(SRR')lPF6 (P-P = Ph2PCH2PPh2 (dppm), PIitPCtH-iPPI^ (dppe), R = Me, Et, Ph, R' = 3-propenyl, 3-cyclohexenyl, 2-methyl-2-buten-4-yl) and [CpRu(chir)(SRR')]PF6 (chir = (S,S)-Ph2PCHMeCHMePPh2, R = Me, CH2Ph, R' = 2-methyl-2-buten-4-yl) are obtained from the corresponding thiolate complexes by reaction with the appropriate allyl bromide. Careful oxidation with dimethyldioxirane (DMD) gave the allyl sulfoxide complexes [CpRu(P-P)(MeS(0)CH2CH=CH2)]PF6 (P-P = dppm, dppe). Double ox idation to the corresponding sulfinylmethyl epoxide complexes can be readily achieved with an excess of DMD. Oxidation of the chir complexes proceeds with only moderate diastereoselectiv-ity. The structure of the (/?, R/S, S) diastereomer of [CpRu(dppm)(MeS(0)CH2CHCH2 0)]PF6 was determined: monoclinic space group P2]/c (No. 14), a = 11.21(2), b = 16.762(9), c = 18.45(4) A, ß = 94.4(1)°, Z = 4. For a representative example, the decomplexation of the sulfoxide-epoxide ligand by sodium iodide in acetone was demonstrated. | | | |
Reference
| Z. Naturforsch. 52b, 1359—1371 (1997); received September 9 1997 | | | |
Published
| 1997 | | | |
Keywords
| Ruthenium Complexes, Sulfoxide, Epoxide, Dimethyldioxirane, Structure | | | |
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| default:Reihe_B/52/ZNB-1997-52b-1359.pdf | | | | Identifier
| ZNB-1997-52b-1359 | | | | Volume
| 52 | |
| 3 | Author
| Bernhard Steinmetz, Michael Hagel, WolfdieterA. Schenk | Requires cookie* | | | Title
| Synthesis and Oxidation of Ruthenium Allyl Thioether Complexes Bearing Phosphite and Phosphonite Coligands [1] | | | | Abstract
| Halfsandwich ruthenium thiolate complexes bearing electron-withdrawing phosphite or phos phonite ligands were prepared from [CpRu(PPh3)2(SR)l (R = Ph, CH2Ph, Me) and triph-enylphosphite or (5,5')-bis(binaphthylphosphonito)ethane (bbpe), respectively. Reaction with l-bromo-3-methyl-2-butene in the presence of NH4PF6 gave the corresponding allylthioether complexes [CpRu(PR'3)2(S(R)CH2CH=CMe2)]PF6. Treatment with an excess of dimethyl dioxirane (DMD) transformed the triphenylphosphite derivatives into diastereomeric (oxiranyl-methyl)sulfoxide complexes with 18 -80% de. NMR monitoring of the reaction revealed that the oxidant attacks the sulfur atom and the C=C double bond with comparable rates. Sim ilar oxidation of the bbpe complexes gave mixtures of four diastereoisomers with ratios of (64 : 15 : 1 3 :8) and (51 : 24 : 15 : 10), respectively. | | | |
Reference
| Z. Naturforsch. 54b, 1265—1271 (1999); received July 2 1999 | | | |
Published
| 1999 | | | |
Keywords
| Ruthenium Complexes, Thioether, Sulfoxide, Epoxide, Dimethyldioxirane | | | |
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| default:Reihe_B/54/ZNB-1999-54b-1265.pdf | | | | Identifier
| ZNB-1999-54b-1265 | | | | Volume
| 54 | |
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